Differential fluid pressure actuated electrical switch

ABSTRACT

A differential fluid pressure actuated electrical switch that includes first and second resilient hollow deformable bodies, the interiors of which are connected to first and second sources of fluid at variable pressures, with said first source normally being at a higher fluid pressure than that in said second source. Parallel first and second force-exerting members project from said bodies, and bear against an elongate, movable actuator, which actuator when moved in a first direction, moves a springactuated member of an electrical switch from a first to a second position to either open or close said switch. The actuating member is moved from said first to said second position only when the pressure of fluid in said second body is at a predetermined, elevated pressure differential relative to the fluid in said first body.

United States Patent Possell [451 Jan. 18,1972

[72] inventor: Clarence R. Possell, 4842 Viane Way, San

Diego, Calif. 92110 22 Filed: Oct. 20, 1969 211 Appl.No.: 867,437

[52] [1.8. Ci. ..200/83 D, 92/34, 92/43, 200/83 B [51] Int. Cl. ..l-i0lh35/32, F01b 19/04, F16j 3/00 [58] Field of Search ..200/83 D, 83.2 B, 83C, 81.5;

[56] References Cited UNITED STATES PATENTS 2,427,426 9/1947 Swenson etal. ..200/83.31 X 2,557,929 6/1951 Baak ..200/83.31 X 2,658,392 10/1953Vannah.... ZOO/83.31 UX 2,685,305 8/1954 Woods ..92/34 X 2,751,4576/1956 Donaldson... ZOO/83.31 X 2,811,925 11/1957 Crookston ...92/34 X3,187,639 6/1965 Kelly et al.... ..92/47 2,961,507 11/1960 l-liggs..200/83.3

FOREIGN PATENTS OR APPLICATIONS 145,323 7/1920 GreatBritain ..92/91543,922 3/1942 GreatBritain ..200/83.3i

Primary Examiner-Robert K. Schaefer Assistant Examiner-Robert A.Vanderhye Attorney-William C. Babcock [57] ABSTRACT A differential fluidpressure actuated electrical switch that includes first and secondresilient hollow deformable bodies, the interiors of which are connectedto first and second sources of fluid at variable pressures, with saidfirst source normally being at a higher fluid pressure than that in saidsecond source. Parallel first and second force-exerting members projectfrom said bodies, and bear against an elongate, movable actuator, whichactuator when moved in a first direction, moves a spring-actuated memberof an electrical switch from a first to a second position to either openor close said switch. The actuating member is moved from said first tosaid second position only when the pressure of fluid in said second bodyis at a predetermined, elevated pressure differential relative to thefluid in said first body.

1 Claims, 6 Drawing Figures PATENTEUJANIBIHH 35636289 FIG. Z

FIG.5

CLARENCE E. P035544 flrrole/var DIFFERENTIAL FLUID PRESSURE ACTUATEDELECTRICAL SWITCH- BACKGROUND OF THE INVENTION sure actuated electricalswitch of a high degree of reliability has been available for opening orclosing an electric circuit. The present invention provides adifferential fluid pressure actuated electrical switch which overcomesnumerous operational disadvantages found in prior art devices of thistype.

SUMMARY OF THE INVENTION A differential fluid pressure actuatedelectrical switch in which first and second toroidal, hollow resilientbodies are connected to first and second sources of fluid under variablepressures. First and second parallel force-exerting members project fromthe first and second bodies and bear against a movable actuator. Whenthe actuator is moved in a first direction it in turn moves aspring-loaded actuating member of an electric switch from a first to asecond position.

The actuator moves said actuating member from the first to the secondposition, only when the fluid in the second body is at a predeterminedelevated pressure differential relative to the pressure of fluid presentin the first body.

A major object of the present invention is to provide a compact,lightweight differential fluid pressure actuated electrical switch ofsimple mechanical structure, that is temperature stable, has a highdegree of reliability in operation, and that requires a minimum ofmaintenance attention.

BRIEF DESCRIPTION OF THE DRAWING FIG. I is a perspective view of a firstform of differential fluid pressure actuated electrical switch;

FIG. 2 Ba longitudinal cross-sectional view of the switch shown in FIG.1, taken on the line 2-2 thereof;

FIG. 3 is a transverse cross-sectional view of the switch, taken on theline 3-3 of FIG. 2;

FIG. 4 is an enlarged, transverse cross-sectional view of one of theresilient fluid-pressure deformable bodies used in the actuation of theswitch;

FIG. Sis a fragmentary, transverse cross-sectional view of the switchshown in FIG. 2, taken on the line 5-5 thereof; and

FIG. 6 is a longitudinal cross-sectional view of a second form offluid-actuated electrical switch.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A differential fluid pressureactuated switch A is shown in perspective in FIG. 1, and in structuraldetail in FIGS. 2-5, which includes an electrical connector 8 ofconventional design. A housing B is provided that is preferablycylindrical,

A slotted first protuberance 34 is formed at the junction of arms 16 and18, with the protuberance serving to support a thin elongate metallicmember 36 that is stiff but somewhat resilient. An elongate rigidactuator 38 is transversely positioned in housing B, forwardly of frameC. A slotted second protuberance 40 extends rearwardly fromsubstantially the center actuator 38, with the second protuberanceengaging the forward end of member 36 to support the actuator therefrom.

A tapped bore 42 (FIG. 2) extends through actuator 38 adjacent arm 16.Bore 42 is engaged by a screw 44 which serves as a first force-receivingmember. A lock nut 46 serves to hold the screw 44 in a desired positionrelative to the actuator 38. A second force-receiving member 48 ismounted on the actuator 38 adjacent to the switch 24, and projectsforwardly from the actuator.

A front piece D is provided that includes a square or rectangularmounting plate 50 (FIG. I) in which a number of screw- 7 receivingopenings 52 are formed and in spaced relationship. First and secondbosses 54 and 56, respectively, extend forwardly from the plate 50, andfirst and second fluid passages 54a and 56a, respectively, are formedtherein. A grooved circular extension 58 extends rearwardly from themounting plate 50, with this extension supporting a resilient O-ring 60,as shown in FIG. 2. The extension 58 and O-ring 60 are of such diameteras to snugly and slidably engage the side wall 10 adjacent to the openend 12. Front piece D and housing B are removably secured together byconventional means (not shown).

First and second toroidal hollow bodies 62 (FIG. 2) are mounted in theinterior of the housing B and located in transversely spacedrelationship. Each body 62 includes flat forward and rear centralportions 63 and 64, respectively, as shown in FIG. 4. A stiff externallythreaded tube 65 is welded to each forward portion 63 and alongitudinally extending bore 66 is formed in each of these tubes thatis in communication with the interior of one of the bodies 62. Thethreaded tubes 65 engage the rear tapped portions of the passages 54aand 56a to place the interiors of the bodies 62 in communicationtherewith. The tubes 65 are sufficiently stiff as to serve to supportthe bodies 62 from the front piece D.

A force-imparting member 68 projects rearwardly from the central portionof the first body 62, 64, and member 68 is in longitudinal alignmentwith the force-receiving screw 44. A second force-imparting member 70projects from the rear portion 64 of the second body 62, with the member70 being in longitudinal alignment with the force-receiving member 48.The device is temperature stable. Any variation in temperature resultsin equal expansion or contraction of the two bodies 62, and as a resultsuch variations cause no differential in the forces exerted by members68 and 70 on member 48 and screw 44.

comprising a continuous sidewall 10 having a first open end l2, and asecond closed end 14 in which the connector 8 is supported.

A cross-shaped frame C is disposed in the rear interior of housing B.Frame C comprises an upwardly extending first arm 16, a seconddownwardly extending arm 18, and two oppositely extending third andfourth arms 20 and 22. A forwardly extending electric switch 24 issupported on the lower free end of second arm 18, as shown in FIG. 2 and3.

A spring-loaded actuating member 26 extends forwardly from switch 24,and normally occupies a first forward position (FIG. 2). First, second,and third electrical conductors 28, 30, and 32 lead from switch 24 andare connectedto parallel, spaced pin-receiving sockets supported infixed positions in connector 8.

A bore 72 extends through the arm 16 and a screw 74 extendstherethrough, which screw supports a generally U- shaped stop 76provided on the forward end thereof. Two locknuts 78 permit the screw 74and stop 76 to be located at a desired adjusted position relative to thearm 16. The switch 24 is of a type, which when a pronged jack forming apart of an electric circuit (not shown) engage sockets 28a and 30a inconnector 8, and the actuating member 26 is in the first position, asshown in FIG. 2, the electric switch 24 maintains the circuit in an opencondition. However, if the sockets 30a and 320 are engaged by a prongedjack fonning a part of an electric circuit (not shown) and the actuatingmember 26 is in the first position (FIG. 2), the switch is closed andcompletes the circuit.

The source of fluid (not shown) connected to the passage 54a is normallyat a pressure higher than that of the source of fluid connected to thepassage56a. The pressure of the fluid in the first body 62longitudinally defonns the same and moves the first force-impartingmember 68 rearwardly to exert a force on the force-receiving screw 44.Due to the force received by screw 44, the actuator 38 is moved until afirst free end 38a thereof contacts a first surface 760 defined in thestop 76.

Should the pressure on fluid supplied to the second passage 56a riseabove the fluid pressure in the first passage 54a and first body 62, thesecond body will deform longitudinally. Longitudinal deformation ofsecond body 62 results in rearward movement of the second force-exertingmember and pivoting the actuator 38 in a counter clockwise direction(FIG. 2). This pivotal movement of actuator 38 causes the actuatingmember 26 to be moved from a first to a second position to pen or closeswitch 24. Pivotal movement of actuator 38 in a counter clockwisedirection is limited by the end 380 of actuator 38 when it contactssurface 76b of stop 76. Thus, no matter how high the pressure of fluidin second body 62, the force-imparting member 70 cannot move rearwardlyto the extent that it pivots actuator 38 to a degree that an excessiveforce is exerted on actuating member 26 of switch 24.

Two elongate, laterally spaced posts 80 extend rearwardly from extension58 and are in longitudinal alignment with arms and 22, the rear surfacesof the posts abut against the forward surfaces of the arms 20 and 22.Screws 82, as may be seen in FIG. 3, extend through openings (not shown)in arms 20 and 22 and engage tapped bores (not shown) formed in the rearportions of posts 80. Due to the above described structure, that portionof the invention inside housing B may be removed therefrom when thefront piece D is separated from the housing. Conductors 28, 30 and 32are fabricated with substantial slack therein to permit that portion ofthe invention in the housing to be removed therefrom through the openend 12.

The use and operation of the differential fluid pressure actuatedelectrical switch has been previously described in detail and need notbe repeated. When the hollow bodies 62 are relatively small, it has beenfound desirable to form them of electroless nickel. In the larger sizes,the hollow bodies 62 are relatively small, it has been found desirableto form them of electroless nickel. In the larger sizes, the hollowbodies 62 are preferably formed from stainless steel sections, weldedtogether. The wall thickness of the bodies 62 may be relatively thin,and will withstand high fluid pressures without damage. From experienceit has been found that when the wall thickness of one of the bodies 62is but 0.020 inches, the interior ,of the body may be subjected to afluid pressure of 6,500 pounds per square inch without any detrimentaleffects. Due to the configuration of the bodies 62, the wall sectionsthereof are under tension only, when subjected to fluid pressure. Eachbody 62 as shown in FIG. 4 has a diameter that is twice the maximumthickness of the body. Due to this configuration deformation of eachbody 62 is linear relative to the pressure applied to the interiorthereof.

A second form E of fluid pressure actuated switch is shown in FIG. 6that includes a housing 82 having an open end 84 that removably receivesa plug 86. Plug 86 supports an electric switch 88 which extends intohousing 82. Switch 88 is placed in either an open or closed condition bya spring-loaded actuating member 90 disposed in housing 82 that normallyoccupies the first position shown in FIG. 6. A connector 92 ofconventional design projects outwardly from plug 86, and is electricallyconnected to the switch by means not shown.

Housing 82 includes a continuous side wall 94 and end wall 96. The endwall 96 supports a tubular fitting 95 that is in communication with ahollow toroidal resilient body 62 of the same structure as the body 62shown in FIG. 4. Body 62 (FIG. 6) is situated inside housing 82,rearwardly from end wall 96. Those portions of the resilient body 62'common to body 62 are identified in FIG. 6 by the same numerals used inFIG. 4, but to which a prime has been added. Force-imparting member 68'extends rearwardly through an opening 98 in a transverse partition 100in housing 82, with the rear end of member 68' being in abutting contactwith actuating member 90 when the actuating member is in a firstposition.

As the pressure on fluid in body 60' increases, the body deformslongitudinally and moves the actuating member 90 rearwardly from thefirst position shown in FIG. 6. After the actuating member 90 is movedrearwardly a predetermined distance to a second position, the switch'88is placed in either an open or closed position. A stop 102 is mounted onforceimparting member 68', as may best be seen in FIG. 6, in such aposition that it contacts partition 100 immediately after the actuatingmember is in the second position. The stop 102 cooperates with partitionto limit the rearward longitudinal deformation of body 62, and preventsexertion of an excessive force against the switch 88 as a result of highfluid pressure in body 62'. When the fluid pressure in body 62' isreleased or lowered, the resiliency of the body returns theforce-imparting member 68' to the position shown in FIG. 6,

whereby the actuating member 90 returns to the first position.

Iclaim:

1. In a differential fluid pressure actuated, temperature stable,electrical switch assembly:

a. a housing that includes first and second ends and a connectingsidewall, said second end having first and second spaced fluid passagesextending therethrough;

b. first and second rigid tubes inside said housing supported from saidsecond end and in communication with said first and second passages,said tubes extending towards said first end;

c. first and second longitudinally deformable hollow resilient toroidalbodies in said housing, which bodies define first and second confinedspaces, with each of said bodies having a diameter substantially twicethe width thereof, and each of said bodies including flat, parallelfirst and second spaced center portions, with said first center portionssecured to the ends of said tubes most adjacent said first end, and theinterior of said bodies in communication with the interior of saidtubes;

(1. first and second force-imparting members that extend towards saidfirst end and are secured to said second center portions of said firstand second bodies;

e. an elongate actuator inside said housing that includes first andsecond force-receiving portions that are axially aligned with said firstand second force-imparting members;

f. a frame supported in a fixed position inside said housing adjacentsaid first end thereof;

g. a stiff but somewhat resilient, thin, elongate member that extendstowards said second end from said frame and on the end most adjacentsaid second end is secured to the center of said actuator to hold saidactuator in a first position, said member of such length that when saidactuator is in said first position said first and second force-impartingand first and second force-receiving portions are in abutting contactwhen the interiors of said first and second bodies are at ambientpressure, said member preventing the center of said actuator movinglongitudinally relative to said housing, but said member allowing saidactuator to pivot relative to said housing; an electrical connectormounted on said first end and extending therethrough;

i. an electric switch assembly mounted on said frame, which assemblyincludes a plurality of wires that extend to said connector, and saidassembly including a spring-loaded actuating member which when in asecond position maintains said switch in either an open or closedcondition, with said actuating member so disposed that it can be movedfrom said second to a third position to reverse the condition of saidswitch when contacted by said actuator when said actuator pivots fromsaid first to a fourth position; and

j. stop means supported from said frame for limiting the pivotalmovement of said actuator from said first position to fourth and fifthpositions, with said first body when fluid therein is at a pressuregreater than that of fluid in said second body deforming towards saidfirst end a greater distance than said first body to cause said firstforce-imparting member to pivot said actuator into said fifth positionwhere said actuating member is not moved, and with said second body whensaid fluid therein is at a pressure greater than that of said fluid insaid first body deforming towards said first end a greater distance thansaid first body and pivoting said actuator into said fourthposition,which actuator when in said fourth position moves said actuating memberto said third position, with said first and second bodies when thepressure on the fluid therein is equal imparting equal forces on saidactual l i I

1. In a differential fluid pressure actuated, temperature stable,electrical switch assembly: a. a housing that includes first and secondends and a connecting sidewall, said second end having first and secondspaced fluid passages extending therethrough; b. first and second rigidtubes inside said housing supported from said second end and incommunication with said first and second passages, said tubes extendingtowards said first end; c. first and second longitudinally deformablehollow resilient toroidal bodies in said housing, which bodies definefirst and second confined spaces, with each of said bodies having adiameter substantially twice the width thereof, and each of said bodiesincluding flat, parallel first and second spaced center portions, withsaid first center portions secured to the ends of said tubes mostadjacent said first end, and the interior of said bodies incommunication with the interior of said tubes; d. first and secondforce-imparting members that extend towards said first end and aresecured to said second center portions of said first aNd second bodies;e. an elongate actuator inside said housing that includes first andsecond force-receiving portions that are axially aligned with said firstand second force-imparting members; f. a frame supported in a fixedposition inside said housing adjacent said first end thereof; g. a stiffbut somewhat resilient, thin, elongate member that extends towards saidsecond end from said frame and on the end most adjacent said second endis secured to the center of said actuator to hold said actuator in afirst position, said member of such length that when said actuator is insaid first position said first and second force-imparting and first andsecond force-receiving portions are in abutting contact when theinteriors of said first and second bodies are at ambient pressure, saidmember preventing the center of said actuator moving longitudinallyrelative to said housing, but said member allowing said actuator topivot relative to said housing; h. an electrical connector mounted onsaid first end and extending therethrough; i. an electric switchassembly mounted on said frame, which assembly includes a plurality ofwires that extend to said connector, and said assembly including aspring-loaded actuating member which when in a second position maintainssaid switch in either an open or closed condition, with said actuatingmember so disposed that it can be moved from said second to a thirdposition to reverse the condition of said switch when contacted by saidactuator when said actuator pivots from said first to a fourth position;and j. stop means supported from said frame for limiting the pivotalmovement of said actuator from said first position to fourth and fifthpositions, with said first body when fluid therein is at a pressuregreater than that of fluid in said second body deforming towards saidfirst end a greater distance than said first body to cause said firstforce-imparting member to pivot said actuator into said fifth positionwhere said actuating member is not moved, and with said second body whensaid fluid therein is at a pressure greater than that of said fluid insaid first body deforming towards said first end a greater distance thansaid first body and pivoting said actuator into said fourth position,which actuator when in said fourth position moves said actuating memberto said third position, with said first and second bodies when thepressure on the fluid therein is equal imparting equal forces on saidactuator in said first position, with said stop means limiting themagnitude of the force that can be exerted by said actuator on saidactuating member irrespective of the differential in pressure on saidfluids in said first and second bodies.